1. Field of the Invention
The present invention relates to heatsink retention systems, and more specifically to tool-less, top-actuated, force limiting heatsink retention systems.
2. Background of the Related Art
A heatsink is commonly used to cool a heat-generating component in electronic equipment, such as a computer system, by transferring thermal energy from the heat-generating component to second object or medium, such as ambient air, at a lower temperature. For example, a processor, such as a central processing unit (“CPU”), generates a considerable amount of heat, and must be reliably cooled to remain operational and prevent damage to the CPU. Accordingly, a variety of methods and devices have been developed for securing a heatsink to a circuit board. The heatsink should be secured in a manner that ensures positive engagement between the heatsink and the heat-generating component to be cooled.
High performance computer systems and server systems include increasingly complex, high signal speed, integrated circuit devices or microprocessors secured to printed circuit boards to accommodate efficient electronic interconnections within a small spatial footprint. These electronic interconnections are commonly made using a land grid array (LGA) that provides high density, mechanically loaded interconnects between the microprocessor and the printed circuit board. The LGA allows for reliable and efficient interconnection, test and replacement of very costly module configurations while circumventing the inherent reliability and process limitations associated with soldering of large area array packages. Yet, the interconnection of a land grid array of a microprocessor to a printed circuit board involves a high area density of electronic contacts that must be highly reliable over a range of operating environments.
Variations in the mechanical load placed on the electronic contacts of the land grid array should be minimized. Such variations have been reduced by using springs to uniformly distribute the applied load and backing plates to provide support to the back side of the printed circuit board. These mechanical systems may also be responsible for the support of heatsinks in direct contact with the microprocessor to support cooling of the microprocessor during operation. Efficient thermal conduction from the processor to the heat sink depends upon uniform contact and mechanical load being applied across the interface between these two components.
Still, the demand for precise positioning, loading, and cooling of microprocessors can be at odds with efforts to provide higher performance in less space. For example, the layout of devices on the printed circuit board must consider spatial interference between adjacent components on the board, as well other adjacent components within the same enclosure. Furthermore, heatsinks and their attachment devices must avoid consuming excessive real estate on the printed circuit board and must work efficiently without employing dimensions that would unduly enlarge the enclosure.